You don't have to know how to sing to be a competent vocalist. Look at Randy Newman - he's made non-singing an artform, and there are plenty others who can't sing that are, again, competent vocalists.
All I can tell you is that plenty of practice will help you find your talent. Also, playing in front of people. When I recorded my very first song, I couldn't understand why there was no "color" or "emotion" in my voice, especially after I made sure my lyrics were on key and all. It sounded very flat and I notice the same thing in your voice. This isn't going to happen overnight, it's only going to happen with praticing your butt off. The reason I don't hear any color or emotion is because like most singers who are just starting out, you're too concerned with getting it right and you're awkward.
I can tell you some techniques. Sing from your gut mainly and if you have to use emphasis like highs and such, then you can use your chest, your throat and your nose. How I teach people to do this is to suck in a breath and then expell it and make a "uh" sound. Then try words, sentences, and then tackle a lyric. If you have to breathe, suck in air through your nostrils. Pretend that the only way you can speak and sing is by using your stomach muscles, you'll find you have far more air to utilize than using your upper chest and throat where you run out. You can also teach yourself vibratto this way!
To strengthen your vocal muscles, prop your mouth open with a pill bottle and sing each vowel sound up and down the music scale. Your vocal chords will hurt first, but if you do this every day, they will start to strengthen. The do them swiveling your head to the side (right then left). You look pretty stupid doing it, but you'll soon have vocal chords of steel.
Once you gain some confidence, you can start tackling bigger things. For instance, learn a few Josh Groban songs and sing along.
http://www.youtube.com/watch?v=fIAQCiMIEEQ
That man can SANG! It's always good to sing along with other singers and pretty soon you'll find your own personality and your own sound.
Learning to sing properly is just as hard work as learning an instrument. I hear singers who do all this stuff just to sing - lemon water, not eating, or people complaining that they lost their voice after a few songs. If you're singing properly, you could sing for a few hours without tiring, especially when you have confidence and you're enjoying what you're doing.
Chaeya
